I'm curious. Where did you hear such nonsense? My little sister (7 year old) plays a whole bunch of online games and I don't see anywhere that it's illegal. I also don't see a cop busting through my door saying "OGMF GET OFF INTRONET. SEVEN YEAR OWLD" Also. One more question.
If it's "illegal" to play online under the age of 13. Then why in the HELL are you here?
Also, most of these people are ~20 years old. One of them is going to be a dad.
You need to learn to COPPA